Should I study Combinatorics and Probability more?

Question

Dear All,

I have started with Q45. After one and half month's study  , got 47. I had always a fear for Combinatorics and Probability from my school days. I decided to give a try afresh. For last 2 days, I have studied gmatclub's documents on those topics and I have understood all the concepts.

Now, when I was trying to solve the sums from walker's post; same problem was happening. I can make out everything from solution but I myself am not able to approach to those solutions.

What should I do? Should I invest more time? or should I just leave these two topics? I am confident with each of other topics. If I leave, how many points should it affect my overall score?

My test is on 7th oct and my target quant score is 49-50!

Please suggest!

DmitryFarberMPrep · Answer

If you're shooting for a top score in quant, you shouldn't leave any major holes in your preparation. Combinatorics and probability can certainly be difficult. We've even made them optional in our course, but then, most of our students aren't targeting 49-50 in Quant. Even at that level, you shouldn't expect to see too many such problems--I think I saw one combinatorics problem on my last official test (Q50)--but it's worth putting some time in (without focusing obsessively on this one area). It's impossible to say how skipping these questions will affect your score, as it depends so much on what happens before/after. Even at Q50, you're still going to be missing questions. If you're very strong elsewhere, it may not be so bad to miss a combinatorics/probability question, but you should get to the point where you at least have a shot at the answer to most of the questions you see.

It's also worth noting that probability problems can often be narrowed down through estimation. Is the even in question likely or unlikely? How much so? If there are several events, is the combined probability higher than any individual probability (OR = add) or lower (AND = multiply)? I've even seen official questions in which one or more of the answer choices presented probabilities greater than one. You can cut those immediately! So if you find it too hard to become a probability master, at least you can, er, increase your probability of guessing the right answer!

raysaranya · Answer

WoW! That's a nice suggestion. I got your point. I won't be obsessed at the same time, knowing the basics for POE.

You did boost up my confidence. Thanks!

GMATPill · Answer

Agree with the assessments above. Focus on the other topics first -- such as word problems, algebra, exponents, fractions, sum of sequences, etc -- then when you are absolutely solid on those, then start getting a feel for combinatorics, etc. Build incrementally -- the foundation will also help you in the more advanced topics later on.

EMPOWERgmatRichC · Answer

Hi raysaranya,

Permutations, Combinations and Probabilities are all relatively rare categories on Test Day - sometimes they can be rather straight-forward questions and sometimes they can be the toughest questions you face. However, you have not defined your overall performance in the Quant sections of your CATs yet, so we can't determine whether you should be spending extra time in these areas yet (or not).

How many FULL-LENGTH CATs (including the Essay and IR sections) have you taken?

On each of these CATs:
1) How many questions did you get wrong overall?
2) How many of those questions did you get wrong because of a silly/little mistake?
3) How many of those questions were about permutations, combinations or probability?

It's quite likely that the missing points that you're looking for can be found in OTHER areas (not in these 3). It's also likely that your OVERALL Score would benefit more if you focused on the Verbal section and improving THOSE skills.

GMAT assassins aren't born, they're made,
Rich

	Target Test Prep - Save up to $599 $400 Discount + $99 Bonus GMAT Club Tests
	e-GMAT: 60% Off on GMAT Focus Get to 735+ from any starting point
	Magoosh increases your score, guaranteed - 15% off ALL Magoosh GMAT plans with code GMATCLUB15 + Free GMAT Club Tests.
	Manhattan Prep: $99 Bonus Score Higher on Your GMAT Exam. Guaranteed.
	Experts' Global - ~~$1720~~ $960 End-to-End GMAT Prep + App Support: 150+ Videos, 2000+ Questions, 15 FLTs +
	GMATWhiz - $299 ~~$499~~ Experience the course through a free trial.
	GMAT Club Tests - Free Included with every course purchase of $149+ View all deals

Should I study Combinatorics and Probability more?

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards